Studies On The Community Characteristics, Vegetative Propagation Technique And Environmental Adaptability Of Distylium Chinense (Fr.) Diels In The Submerged Area Of The Three-Gorges Reservoir Region

Six natural populations of Distylium chinense (Fr.) Diels at the submerged areas along banks of Wuxia and Daning River in Three-Gorges Reservoir Region were investigated. Vegetative propagation techniques as cuttage, engraftment and its adaptation to the stress of environmental factors have been studied. The result reveals as follows:Fern and angiosperm are the major vascular plants in the primary habitat of D. chinense (Fr.) Diels. There are 13 species of 9 genera in 7 families of ferns and 61 species of 48 genera in 29 families of angiosperm in the communities where D. chinense (Fr.) Diels populated. The species composition in the communities shows a transitional floristic character from the tropic to temperate zone.,In the cuttage experiment, the total livability of D. chinense(Fr.) Diels is 82.64%. Among the 16 types of treatments, it is the best combination with IBA200mg/L +IBM400mg/L +NAA100mg/L added, which result in the highest livability. No matter from points of view of livability or from the dry weight of roots, the successful cuttage was promoted by IBA very well, while impeded by 6-BA strongly.In the engraftment experiment with inarching approach using Distylium racemosum Sieb. et Zucc. as stock,the livability could reach 42% even if it could reach 21% through a hot summer in Chongqing. The success of engrafting experiment of Distylium chinense(Fr.) Diels supply another approach for the conservation for the gene resource.After the treatments of D. Chinense (Fr.) Diels under the simulation of acid rains with 5 different pH values. The differences and the stress responses are not significant in the short time of two months. This shows that the species grow in water-level-fluctuating zone of the Three-Gorges Reservoir Region have already developed relatively stronger adaptation to acid rain environment, which ensures invulnerability to strong acid rains.Similarly, extreme alkali stress with pH 12 don't have great influence on the growth of the species, which indicates that D. chinense (Fr.) Diels has strong capacity of adaptation to alkali stress.Performance of the species under high salinity (0.9%, 1.5%) treatment is notably different from other treatments. Higher salinity will lead to the dehydration, the...